A new instrument is proposed for the study of monomolecular organic films. The ellipsometer consists of an imaging ellipsometric viewfinder and a one-spot thickness measuring photometer visible in the viewfinder. With the viewfinder monomolecular protein spots can be seen on the surface of a slide, so that sample homogeneity and quality can be assessed before the photometer is used. It is also possible to see the size of diffusion zones or rapidly examine a large area for some feature. The photometer has an aiming index in the eyepiece and uses the intensity at that point to measure the film thickness or the mass of the organic film. The operation is very simple and straight- forward with a computer converting the light intensity to organic mass. The instrument is suitable for automation and unattended operation, while retaining full manual capabilities. The ellipsometer can be used to measure all monomolecular protein films, and the screening of antibody-producing hybridomas for production quantity and antibody properties is but one application.